A network storage device is an application system that stores data of a user on the Internet. Whenever and wherever possible, the user can upload a file to the network storage device, can download a file from the network storage device, can manage a file stored in the network storage device, or can share a file stored in the network storage device with another person.
Currently, most network storage devices are implemented using a network hard disk that has a network function. The network storage device is based on a hard disk that supports the serial attached SCSI (SAS) (where SCSI referred to small computer system interface)/a serial at attachment (SATA) hard disk, a converting circuit is added to an exterior of the hard disk, and a network interface is provided using the converting circuit. FIG. 1 is a schematic structural diagram of an existing network storage device, and FIG. 2 is a cross-sectional view of a storage shelf in FIG. 1 in an A-A direction. As shown in FIG. 1, a cabinet 14 includes a network switch 11 and multiple storage shelves 12, the storage shelves 12 are connected to the network switch 11 using a cable 13 to implement a function of storing data of a device and a user, and the multiple storage shelves 12 are installed inside the cabinet 14 in stack mode. As shown in FIG. 2, a switch board 21, a heat dissipation unit 22, and a hard disk area 23 are integrated in each storage shelf 12, and multiple hard disk units 24 can be disposed in the hard disk area 23, to form a storage array.
However, as network users gradually increase, a requirement for a network storage capacity is increasingly high. When a solution in the prior art is used for expansion, storage shelves need to be expanded one by one, storage density is limited, and expansion flexibility is not high.